Rapid Growth Slow Growth Negative Growth (Kenya) (United States) Germany) Male Female Age Male Female Year of Birth Male Female Before 1915 915-1919 1920-1924 Postreproductive 1925-1929 1930-1934 50·54 1940-1944 45-49 1945-1949 40-44 1950-1954 35-39 1955-1959 Reproductive 1964-1969 1970-1974 Prereproductive 1985-1989 1990-1994 Percent of population Percent of population Percent of population in each of the three categories are good clues to the future growth of g viduals Age Distribution in Human Populations The relative numbers of ing population
Age Distribution in Human Populations Age Distribution in Human Populations The relative numbers of individuals in each of the three categories are good clues to the future growth of a population
Population Density and Spatial Distribution Population Density -Number of individuals per unit area Dispersal -Movement of individuals from densely populated locations to new areas Emigration -Out movement 今 mmigration- n Movement
Population Density and Spatial Distribution • Population Density - Number of individuals per unit area. – Dispersal - Movement of individuals from densely populated locations to new areas. Emigration - Out movement Immigration - In Movement
Population Growth Curve Biotic Potential -Inherent reproductive capacity Generally, biotic potential is much above replacement level Natural tendency for increase All living populations follow an exponential growth curve
Population Growth Curve • Biotic Potential - Inherent reproductive capacity. – Generally, biotic potential is much above replacement level. Natural tendency for increase. – All living populations follow an exponential growth curve
Geese Pi Biotic Potential The ability of a species to reproduce greatly exceeds the number necessary to replace those who die. Here are some examples of the prodigious reproductive abilities of some species
Biotic Potential Biotic Potential The ability of a species to reproduce greatly exceeds the number necessary to replace those who die. Here are some examples of the prodigious reproductive abilities of some species
Exponential Growth Curve Lag Phase-First portion of the curve-slow population growth EXponential Growth Phase -More organisms reproducing causing accelerated growth continues as long as birth rate exceeds death rate Stable Equilibrium Phase- Death rate and birth rate equilibrate -population stops growing
Exponential Growth Curve • Lag Phase - First portion of the curve - slow population growth. • Exponential Growth Phase - More organisms reproducing causing accelerated growth - continues as long as birth rate exceeds death rate. • Stable Equilibrium Phase - Death rate and birth rate equilibrate - population stops growing